Zygopauropus

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Zygopauropus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Myriapoda
Class: Pauropoda
Order: Tetramerocerata
Family: Brachypauropodidae
Genus: Zygopauropus
MacSwain & Lanham, 1948
Species:
Z. hesperius
Binomial name
Zygopauropus hesperius
MacSwain & Lanham, 1948

Zygopauropus is a monotypic genus of pauropod in the family Brachypauropodidae. [1] The only species in this genus is Zygopauropus hesperius, [1] which is found in the western United States. [2] This genus is notable as one of only four genera of pauropods in which adults have only eight pairs of legs rather than the nine leg pairs usually found in adults in the order Tetramerocerata. [3] Before the discovery of Zygopauropus, adult pauropods were thought to have only nine or (rarely) ten pairs of legs. [4]

Contents

Discovery

The genus Zygopauropus and its type species Z. hesperius were first described by the zoologists John W. MacSwain and Urless N. Lanham of the University of California at Berkeley in 1948. MacSwain and Lanham based their descriptions on twelve specimens that they collected in 1947. These specimens include a male holotype, a female allotype, four paratypes (one male and three females), and four juveniles representing the first three stages of post-embryonic development, all found on the south slopes of Mount Diablo in Contra Costa county in California. MacSwain and Lanham also found two adult male specimens in the town of Fairfax in Marin county in California. [4]

Description

This pauropod is small and white: the adult male holotype measures only 0.54 mm in length and 0.17 mm in width, and the adult female allotype measures only 0.56 mm in length and 0.20 mm in width. [4] This species features a head with four transversal rows of setae. [5] [3] Three tube-like extensions (one anterior, one median, and one posterior) protrude from the temporal organ on each side of the head. [2] [3] [5]

Adults have only eight pairs of legs, and each leg has five segments. [4] [5] [3] [2] These pauropods go through the first four stages of post-embryonic development typical of species in the order Tetramerocerata, with three leg pairs in the first stage, five pairs in the second, six pairs in the third, and eight pairs in the fourth, but reach sexual maturity in the fourth stage rather than in a fifth stage and do not add the ninth pair of legs that usually appear in a fifth stage for other species in this order. [4] [3] Thus, adults of this species also have only eleven trunk segments and five tergites and do not acquire the twelfth trunk segment and sixth tergite that other species in this order usually add in a fifth stage. [3] [6]

The first tergite is entire, with a single sclerite featuring four pairs of setae. The second, third, and fourth tergites are each divided both transversely and longitudinally, with each quadrant featuring a pair of setae. The fifth tergite is divided longitudinally into two sclerites, each with five setae. The setae on the tergites are bristle-shaped or slightly hastate; these setae bend near the base to point toward the posterior. The sternum of the pygidium features two pairs of setae, one anterior and one posterior. [4]

MacSwain and Lanham also described two other new genera in the family Brachypauropodidae, Aletopauropus and Deltopauropus, along with Zygopauropus, finding no more than eight pairs of legs in all three genera. [4] Since then, the genus Deltopauropus has been found to include adults with the usual nine leg pairs, but no adults with more than eight leg pairs have been found in the genera Zygopauropus and Aletopauropus. [3] [5] Since the description of Zygopauropus and Aletopauropus by MacSwain and Lanham, only two other genera of pauropods, Amphipauropus and Cauvetauropus, have been found to have adults with no more than eight leg pairs. [3]

Pauropods in the genus Zygopauropus share several traits with other pauropods in the family Brachypauropodidae. These traits include not only an entire first tergite followed by second and third tergites that are each divided into at least four parts but also a pygidial sternum with at least two pairs of setae. [3] The genus Zygopauropus shares an especially extensive set of traits with the genus Aletopauropus, the only other genus in the family Brachypauropodidae in which adults have only eight leg pairs. For example, both genera have only two pairs of setae on the pygidial sternum, bristle-shaped or hastate setae bent posteriorly near the base on the tergites, and temporal organs with three tube-like extensions. [3] [5]

Pauropods in the genus Zygopauropus can be distinguished from those in the genus Aletopauropus based on other traits. For example, the fifth tergite in Zygopauropus is divided into two parts, whereas this tergite in Aletopauropus is entire. Furthermore, the head features four transversal rows of setae in Zygopauropus but only three transversal rows of setae in Aletopauropus. [3] [5]

Related Research Articles

<span class="mw-page-title-main">Pauropoda</span> Class of arthropods

Pauropoda is a class of small, pale, millipede-like arthropods in the subphylum Myriapoda. More than 900 species in twelve families are found worldwide, living in soil and leaf mold. Pauropods look like centipedes or millipedes and may be a sister group of the latter, but a close relationship with Symphyla has also been posited. The name Pauropoda derives from the Greek pauros and pous or podus, because most species in this class have only nine pairs of legs as adults, a smaller number than those found among adults in any other class of myriapods.

<span class="mw-page-title-main">Symphyla</span> Class of many-legged arthropods

Symphylans, also known as garden centipedes or pseudocentipedes, are soil-dwelling arthropods of the class Symphyla in the subphylum Myriapoda. Symphylans resemble centipedes, but are very small, non-venomous, and only distantly related to both centipedes and millipedes. More than 200 species are known worldwide.

<span class="mw-page-title-main">Myriapoda</span> Subphylum of arthropods

Myriapods are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial.

<span class="mw-page-title-main">Pauropodidae</span> Family of many-legged arthropods

Pauropodidae is the most diverse family of pauropods, containing 27 genera and more than 800 species. This family has a subcosmopolitan distribution. These pauropods usually live in the soil on mountains and hills. This family also includes the only known fossil pauropod (Eopauropus).

<i>Pulmonoscorpius</i> Extinct species of scorpion

Pulmonoscorpius is an extinct genus of scorpion from the Mississippian of Scotland. It contains a single named species, Pulmonoscorpius kirktonensis. It was one of the largest scorpions to have ever lived, with the largest known individual having an estimated length exceeding 70 cm. Pulmonoscorpius retains several general arthropod features which are absent in modern scorpions, such as large lateral eyes and a lack of adaptations for a burrowing lifestyle. It was likely an active diurnal predator, and the presence of book lungs indicate that it was fully terrestrial.

<span class="mw-page-title-main">Glomerida</span> Order of millipedes

Glomerida is an order of pill-millipedes found primarily in the Northern Hemisphere. Also known as northern pill millipedes, they superficially resemble pill-bugs or woodlice, and can enroll into a protective ball. They have twelve body segments, 17 to 19 pairs of legs, and males have enlarged rear legs involved in mating. The order includes about 30 genera and at least 280 species, including Glomeris marginata, the common European pill-millipede. The order contains members in Europe, South-east Asia and the Americas from California to Guatemala. Although historically considered closely related with the similar sphaerotheriidans that also enroll, some DNA evidence suggest they may be more closely related to glomeridesmidans, a poorly known order that does not enroll.

<span class="mw-page-title-main">Polyxenida</span> Order of millipedes

Polyxenida is an order of millipedes readily distinguished by a unique body plan consisting of a soft, non-calcified body ornamented with tufts of bristles. These features have inspired the common names bristly millipedes or pincushion millipedes. This order includes about 148 species in four families worldwide, which represent the only living members of the subclass Penicillata.

Millotauropus is a genus of pauropods in the monotypic family Millotauropodidae in the monotypic order Hexamerocerata. The order Hexamerocerata includes only eight species and was created in 1950 to contain the newly discovered genus Millotauropus, which was found to have so many distinctive features as to warrant placement in a separate order. Before the discovery of Millotauropus, for example, pauropods were thought to have no more than ten leg pairs, but adults in the order Hexamerocerata have eleven pairs of legs.

Tetramerocerata is an order of pauropods containing 11 families and more than 900 species. This order was created in 1950 to distinguish these pauropods from those in the newly discovered genus Millotauropus, which was found to have such distinctive features as to warrant placement in a separate order (Hexamerocerata) created to contain that genus. The order Tetramerocerata includes the vast majority of pauropod species, as there are only eight species in the order Hexamerocerata, which remains the only other order in the class Pauropoda.

Eopauropus balticus is a prehistoric pauropod known from mid-Eocene Baltic amber. It is the only known pauropod in the fossil record. As pauropods are normally soil-dwelling, their presence in amber is unusual, and they are the rarest known animals in Baltic amber.

Brachypauropodidae is a family of pauropods. This family has a nearly worldwide distribution. Pauropods in this family are found on all continents except South America and Antarctica.

<span class="mw-page-title-main">Scolopendrellidae</span> Family of many-legged arthropods

Scolopendrellidae is a family of symphylans in the class Symphyla. There are about 9 genera and at least 100 described species in Scolopendrellidae.

<span class="mw-page-title-main">Scutigerellidae</span> Family of many-legged arthropods

Scutigerellidae is a family of pseudocentipedes in the class Symphyla. There are about 5 genera and at least 140 described species in Scutigerellidae.

Decapauropus is a large genus of pauropods in the family Pauropodidae that includes more than 300 species. This genus was originally described by the French zoologist Paul Remy in 1931 to contain the newly discovered type species Decapauropus cuenoti. As the name of this genus suggests, this genus is notable for including females with ten pairs of legs instead of the nine leg pairs usually found in adult pauropods in the order Tetramerocerata. Before the discovery of D. cuenoti, adult pauropods were thought to have invariably nine pairs of legs.

Agenodesmus is a genus of millipedes in the family Fuhrmannodesmidae, which some authorities consider a junior synonym of Trichopolydesmidae. This genus is notable for being among the very few genera in the order Polydesmida to feature adults with only 18 segments rather than the 20 segments usually found in this order. The genus Agenodesmus contains only two species, A. reticulatus and A. nullus. The type species A. reticulatus is notable as the first polydesmidan millipede discovered with only 18 segments in adults, the smallest number recorded in the order Polydesmida. Before the discovery of A. reticulatus, polydesmidans were known to have only 19 or 20 segments in adults.

Neocambrisoma is a genus of millipedes in the family Metopidiotrichidae. Millipedes in this genus are found in Tasmania and New South Wales in Australia. Like other genera in this family, this genus features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, female adults in this genus have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.

Decapauropus cuenoti is a species of pauropod in the family Pauropodidae. As the name of the genus Decapauropus suggests, this species is notable for including females with ten pairs of legs instead of the nine leg pairs usually found in adult pauropods in the order Tetramerocerata. Before the discovery of D. cuenoti, adult pauropods were thought to have invariably nine pairs of legs.

Devilliea tuberculata is a species of flat-backed millipedes in the family Xystodesmidae. Like other members of the genus Devillea, this species is limited to caves. This millipede has been found in several caves in the Alpes-Maritimes department of France. This species is notable as the first millipede in the order Polydesmida found to feature more than the 20 segments usually found in this order.

Neocambrisoma raveni is a species of millipede in the family Metopidiotrichidae. These millipedes are found in New South Wales in Australia. Like other species in this family, N. raveni features 32 segments in adults of both sexes, rather than the 30 segments usually observed in adults in the order Chordeumatida. Accordingly, adult females of this species have 54 pairs of legs, which is not only the maximum number observed in this order but also the maximum number fixed by species in the class Diplopoda.

References

  1. 1 2 "ITIS – Report: Zygopauropus". www.itis.gov. Retrieved 2024-02-25.
  2. 1 2 3 Scheller, Ulf (1985). "On the Classification of the Family Brachypauropodidae (Myriapoda; Pauropoda)". Bijdragen tot de Dierkunde. 55 (1): 202–208 – via Naturalis Repository.
  3. 1 2 3 4 5 6 7 8 9 10 11 Scheller, Ulf (2011). "Pauropoda". Treatise on Zoology – Anatomy, Taxonomy, Biology. The Myriapoda, Volume 1: 467–508. doi:10.1163/9789004188266_022. ISBN   9789004156111.
  4. 1 2 3 4 5 6 7 MacSwain, J.W.; Lanham, U.N. (1948). "New genera and species of Pauropoda from California". Pan-Pacific Entomologist. 24 (2): 69–84 – via Biodiversity Heritage Library.
  5. 1 2 3 4 5 6 Scheller, Ulf (2008). "A reclassification of the Pauropoda (Myriapoda)". International Journal of Myriapodology. 1 (1): 1–38. doi: 10.1163/187525408X316730 . ISSN   1875-2535.
  6. ↑ Scheller, Ulf; Adis, Joachim (2000). "Possible parthenogenesis in Allopauropus (Myriapoda: Pauropoda)". In Wytwer, Jolanta; Golovatch, Sergei (eds.). Progress in studies on myriapoda and onychophora: Proceedings of the 11th International Congress of Myriapodology, 20-24 July 1999, Białowieża, Poland. Fragmenta faunistica. Warszawa: Museum and Institute of Zoology, Polish Academy of Sciences. pp. 171–77. ISBN   978-83-85192-96-1.
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